Method for washing chips

ABSTRACT

A METHOD FOR CONTINUOUSLY WASHING CHIPS SO AS TO REMOVE PARTICLE IMPURITIES IN AN ARRANGEMENT WHICH CAUSES THE CHIPS TO PASS IN A HELICAL PATH, THE LOWER PART OF WHICH RUNS THROUGH A WASHING LIQUID.

8- 1972 J. L. A. LARSSON 3,687,733

METHOD FOR "ASKING CHIPS F1104 luv. 19. 1969 5 ShutI-Sllut 1 Aug. 29, 1'12 .1. L. A. LARSSON IETHOD FOR WASHING CHHS 5 Shuts-Shut 2 u n-a m. 19. 1969 mi r W L lliv \\\\\l\\\\\\ iiiiiiiiliiiifiiii NN!!! I- 1'72 J. L. A. LARSSON 3,687,733

METHOD FOR WASHING CHIPS Filed Nov. 19, 1969 5 Shanty-Shut 3 FIG.3

Aug. 29, 1.12

Find Iov. 19, 1969 J. L- A. LARSSON METHOD FOR ASKING CHIPS 5 Shuts-Shut 4 I- 29, J. 1.. A. LARSSON 3,687,733

lm'rnon FOR WASHING cans Filed low. 19. 1969 5 Shanta-Shut 5 United States Patent Oflice 3,687,733 Patented Aug. 29, 1972 Int. Cl. Boas 1/00; Boss 3/04 US. Cl. 134-25 R 1 Claim ABSTRACT OF THE DISCLOSURE A method for continuously Washing chips so as to remove particle impurities in an arrangement which causes the chips to pass in a helical path, the lower part of which runs through a washing liquid.

This invention relates to a method of continuously washing chips or the like so that stones, coarse sand and other particle impurities are removed from the chips, and it further relates to an arrangement for carrying out the method.

In the conventional methods of conveying and storing wood chips, the chips in many cases are mixed to a great extent with impurities, such as stones, coarse sand and the like. If such foreign material is allowed to follow with the chips to their subsequent treatment by beating, screening etc., damages easily will be caused at the expensive apparatus equipment. If said impurities together with the chips enter the digesting process, the cooking liquor is contaminated and has to be exchanged at a higher rate. It is, therefore, desired to remove such particle impurities from the chips, for example by washing the chips with a liquid such as water or white liquor.

The invention has as its object to overcome the aforesaid impurity problems. This object is achieved in that the chips during their washing are caused to pass in a helical path, the lower part of which runs through a washing liquid.

One embodiment of the invention is described in greater detail in the following, with reference to the drawings, in which FIG. I shows in a schematic way an arrangement according to the invention seen from one end wall,

FIG. 2 shows the arrangement in FIG. 1 partially in section, seen from one long side,

FIG. 3 shows the arrangement in FIG. 1 partially in section, seen from above,

FIG. 4 is a view, partially in section, along the line 4-4 in FIG. 2,

FIG. 5 is a partial view, partially in section, along the line 5-5 in FIG. 3, and

FIG. 6 is a section along the line 6-6 in FIG. 5.

FIG. 1 shows in a schematic way how the chips to be washed enter the arrangement through an inlet opening 1 at the front end wall 2 of an external tank 3 containing a washing liquid, for example water or white liquor. Within said external tank 3 is arranged an internal cylinder comprising two hollow cylinder portions 4 and 5 whereof one portion 4 is secured on the tank 3. The second portion 5 is a rotor mounted on a shaft 6 about which the rotor is caused to rotate by means of a motor (not shown). Said rotor 5 is provided with a plurality of dog members 7 extending substantially between the tank front end wall 2 and a rear end wall 8 and, thus, also over the stationary cylinder portion 4, see FIG. 2. Upon rotation of the rotor 5 the chips are moved by said dog members about the internal cylinder 4, 5 in the direction indicated by the arrows in FIG. I. Said dog members, furthermore, are designed to as to impart to the chips a translation motion along the cylinder 4, 5, thereby causing the chips during the washing operation to describe a helical path about the internal cylinder 4. 5.

The chips upon their arrival at the tank rear end wall 8 fall down through an opening 9 into the stationary cylinder portion 4, see FIGS. 2 and 3, where they are wetted by a new washing liquid through a pipe or nozzles, see FIG. 3. Said washing liquid thereafter runs down into the tank 3 through openings in the bottom of said internal cylinder 4, 5.

The chips subsequent to their cleansing are conveyed along the rotor 5 in the direction of the arrows, see FIG. 3, by means of a reciprocating feeding attachment 10. The rotor 5 is mounted on the shaft 6 by arms 11 with such inclination that they contribute in conveying the washed chips to the front end wall 2 and out of the chip washer through an outlet opening 12, see FIG. 4. Instead of the feeding attachment 10 a conveyor screw or the like (not shown) may be provided, particularly if it is desired to improve the continuity of the chip flow out of the chip washer.

The arrangement is disposed in connection to a conveyor chute 13 through which the chips to be washed fall. Said conveyor chute 13 is provided with a damper means 14 rendering it possible to select the fraction size of the supplied chips to be washed. Thereby the chip washer can operate at full capacity even when the chip supply temporarily is too great. In such a case, it is true, some part of the chips may enter the subsequent treatment steps in unwashed state, but for many applications this is not of any decisive importance. Said damper means 14 also renders it possible to entirely separate the arrangement from the conveyor chute 13, so that maintenance work can be carried out without having to stop the chip fiow through the conveyor chute 13.

During the washing operation the impurities of a greater weight, for example stones and gravel, are removed from the chips and sink to the bottom of the tank 3. Said bottom is given the shape of a chute 15 with downward inclination toward an outlet 16 to a catching chamber 17 to which the impurities are directed from the tank 3. Said impurity transport to the outlet 16 is effected to some extent by the bottom flows within the washing liquid, which flows have a main direction opposite to the translation mo tion of the chips. The effect of said flows is increased by a bafiie plate 18 as indicated in FIG. i.

The bottom of the catching chamber 17 has V-section, see FIG. 6, and within the chamber is mounted a vane means for the removal of the impurities. Said vane means comprises a blade 19 which is mounted on a rotary shaft 20 by an arm 21 and designed so as to correspond to the V-section of the bottom in said catching chamber 17. The blade 19 is provided with an oblique plate 22 forming an angle both with the plane of blade 19 and with the shaft 20. Upon rotation of shaft 20, thus, the blade 19 collects impurities up from the lower portion of the 3 catching chamber 17 and, after the blade 19 has passed the horizontal position, the impurities on the blade 19 slide downwards along the oblique plate 22 whereafter they leave the catching chamber 17 through an opening 23 in one side of said chamber.

What I claim is:

1. Method for continuously washing chips or the like with a liquid, such as water or white liquor, for removing stones, coarse sand and other particulate impurities from said chips; comprising the steps of feeding the chips to be washed into a tank at a first end thereof, said tank containing a quantity of said liquid to a predetermined free level thereof; conveying said chips in an essentially circular motion about a rotor rotably mounted in said tank in such a fashion that a substantial portion of the chips are withdrawn from the water during each revolution of the rotor and so as to repeatedly move said chips into and out of said liquid; concurrently imparting a translational movement to said chips for conveying the latter toward a second end of said tank remote from said first end, said chips during said circular and translational movements through said tank passing in an essentially helical path the lower portion of which extends through said liquid and the upper portion of which extends above said liquid level; and removing said washed chips from said tank at said second end thereof.

References Cited UNITED STATES PATENTS 693,684 2/ 1902 Burgess 209-173 824,141 6/1906 Powers 209-173 1,548,971 8/1925 Ziska 209-173 1,559,938 11/1925 Chance 209-173 2,422,657 6/1947 Cleveland 209-173 X 2,491,912 12/1949 Walker 209173 X 2,764,289 9/1956 Scheid 209-173 3,297,043 1/1967 Adams 134-25 R X 3,367,495 2/ 1968 Lea et al. 209173 X FOREIGN PATENTS 235,410 7/ 1960 Australia 134-25 R 557,953 2/ 1957 Italy 209-162 20 BARRY s. RICHMAN, Primary Examiner US. Cl. X.R. 

